ceddy.us

Memory Mode

The H8s are in Mode 4 Extended Max
ROM Enabled, with a 16-Bit External Bus
(You can check this by looking at Pins 81-83)

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Address Space

The ROM is Loaded to 10000-2FFFF.

Mirrored Space

10000-13FFF is copied to 0-3FFF.
This allows this lower 4KB to accessed from page 1 or 2 with a single instruction.
And negates the need of changing the page register when accessing addresses out of the current page.

Generally Mitsu uses this space for settings and maps.
Basically everything you edit in EcuFlash is in this lower 4KB.

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LayOut

Mode 4 Extended Max

Page 0:
   0 - 1FF Vector Table
   200 - 3FFF On Chip ROM 16K
   4000 - EE7F Unused
   EE80 - FE7F On Chip RAM 4K
   FE80 - FFFF On Chip Registers 384 Bytes
Page 1:
   10000 - 1FFFF On Chip ROM 64K
Page 2:
   20000 - 2FFFF On Chip ROM 64k

0-3FFF and 10000-3FFF are identical, so I will start my list at 10000.
This list is for the EM2055, but all H8s have these items in the same general area.

10000-1013C

Interrupt Vector Addresses

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10400-101FC

Interrupt Vector Pointer Addresses
Memory address that is loaded with address to sub-routine.

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10200-10322

Identification and Global ROM Settings
ROM and Calibration Id,  Periphery Bits,
and Global Flags that Enable/Disable things like Closed Loop, etc.

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10800-11508

Constants and 1D Data.
Injector Size, MAF Size, RevLimit, etc.

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11800-13B1A

2D and 3D Maps and Tables.
Fuel, Timing, etc.

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Start of Code

14000-15168

Math and Table LookUp Sub-routines.

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15190-1A560

Port and Timers Setup, Inputs and Outputs.

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1A600-1FF03

OBD2 and Emissions Tests

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20000-20A76

Flash Kernel
Loaded to RAM and Executed when a Flash is about to take place.

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20A80-2E1B7

Main Operating Loop and its sub-routines.

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End of Code

2E2E0-2EB4E

Map Axis

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2EB50-2EE8C

Pointers to Maps.
Address to important maps contained here.
Each address is repeated eight times.

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2FAD0-2FED0

MUT Table.